Cardiac arrhythmia is a condition in which the electrical activity of the heart is irregular or is faster or slower than normal. Cardiac arrhythmia may be classified by rate and/or mechanism. For instance, atrial fibrillation (AF) is the most common type of serious arrhythmia that involves a very fast and irregular contraction of the atria. Ventricular fibrillation (VF) is a condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart. Multifocal atrial tachycardia (MAT) is a type of arrhythmia with an irregular atrial rate greater than 100 bpm. Myocardial ischemia (MI) is a type of arrhythmia that occurs when blood flow to the heart muscle is decreased by a partial or complete blockage of the heart's arteries. Myocardial infarction (commonly known as a heart attack) occurs when blood stops flowing properly to part of the heart and the heart muscle is injured due to not receiving enough oxygen.
Early recognition and characterization of arrhythmia is desirable to prevent progress to a life-threatening arrhythmia, such as atrial fibrillation or ventricular fibrillation. Known methods for cardiac arrhythmia detection and diagnosis focus on electrophysiological data and waveform morphologies, such as a QRS complex, ST segment, T wave, U wave, etc. Typically, a 12-lead electrocardiogram (ECG) and multi-channel intracardiac echocardiography (ICE acquired via invasive cardiac catheters) are used for evaluating cardiac rhythm and events. However, these methods are limited, mainly because an early change of cardiac circulation function is shown first in blood contraction and hemodynamic characteristics, and only subsequently in electrophysiological signals.
Accurate clinical assessment of circulatory status is particularly desirable in critically ill patients in an intensive care unit (ICU) and patients undergoing cardiac, thoracic, or vascular interventions. As patient hemodynamic status may change rapidly, it is necessary to continuously monitor cardiac output so as to obtain information that enables rapid adjustment of therapy. Usually, non-invasive blood pressure (NIBP) monitoring and/or least invasive blood pressure monitoring are used to observe hemodynamic changes in cardiac tissue and function.
Conventional methods for cardiac circulation arrhythmia (e.g., atrial fibrillation or AF, myocardial infarction, etc.) detection and diagnosis based on electrophysiological signal (e.g., ECG, ICEG, etc.) morphologies require extensive clinical knowledge and experience for accurate interpretation. Inaccurate, subjective and non-quantitative evaluation and diagnosis may delay detection of a cardiac condition. Known methods based on hemodynamic blood pressure (e.g., NIBP signals) wave morphology changes also fail to efficiently differentiate various cardiac malfunction arrhythmia types and categorize severity of the arrhythmia pathologies. In addition, known cardiac arrhythmia analysis typically lack efficiency and reliability, and are sensitive to noise. Ventricular activity signals may be obscured by noise and artifacts, especially for small patient signals (uV to mV range).
Accordingly, there exists a need to provide an improved framework to address these deficiencies and related problems.